cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A222391 Decimal expansion of e^2/sqrt(Pi).

Original entry on oeis.org

4, 1, 6, 8, 8, 2, 8, 4, 8, 3, 2, 6, 6, 6, 9, 2, 2, 3, 0, 4, 2, 1, 3, 0, 3, 9, 0, 7, 7, 5, 2, 3, 1, 0, 2, 6, 0, 3, 8, 6, 6, 6, 4, 6, 8, 1, 1, 4, 8, 4, 9, 9, 6, 3, 7, 8, 3, 0, 0, 0, 8, 9, 5, 4, 6, 2, 4, 0, 4, 3, 2, 2, 7, 2, 0, 1, 5, 3, 6, 0, 9, 2, 7, 9, 8, 1, 9
Offset: 1

Views

Author

Bruno Berselli, Mar 19 2013

Keywords

Examples

			4.1688284832666922304213039077523102603866646811484996378300089546240432...
		

Crossrefs

Cf. A096789: Sum_{n >= 1} 1/(Gamma(n)*Gamma(n+1)).
Cf. A035009 (see fourth comment).

Programs

  • Maple
    Digits:=100: evalf(exp(1)^2/sqrt(Pi)); # Wesley Ivan Hurt, Jan 09 2017
  • Mathematica
    RealDigits[E^2/Sqrt[Pi], 10, 90][[1]]
  • PARI
    (exp(1))^2/sqrt(Pi) \\ G. C. Greubel, Jan 09 2017

Formula

Equals decimal expansion of Sum_{n >= 1} 1/(Gamma(n/2)*Gamma((n+1)/2)).